This invention relates to a three-dimensional image display apparatus applicable to, for example, a television for the purpose of providing vivid images.
In the description below, the three-dimensional image is considered the same as a stereoscopic image. A stereoscopic image display apparatus which is disclosed in, for example, Japanese Patent Application KOKAI Publication No. 8-249493 is exemplified as the prior art. In this stereoscopic image display apparatus, character information to be displayed three-dimensionally is written beforehand in a memory unit together with left-eye and right-eye positional information. When the positional information has been accessed, a character appears in any optional position in a stereoscopically displayed space, and this character shifts in left/right directions, up/down directions or forward/backward (depth) directions.
Further, in this stereoscopic image display apparatus, an image to be seen by the left eye of a viewer and an image to be seen by the right eye of a viewer are displayed on the screen in a time-division manner. At this time, shutter glasses provided for the apparatus are controlled such that its left-side shutter is open and its right-side shutter is closed while the image to be seen by the left eye is displayed on the screen. On the other hand, the right-side shutter is open and the left-side shutter is closed while the image to be seen by the right eye is displayed on the screen.
A stereoscopic image will be sensed as follows:
The image to be seen by the left eye and the image to be seen by the right eye are displayed on left and right portions of the screen, respectively. As a result, the image L1 to be directed to the left eye of a viewer and the image R1 to be directed to the right eye of the viewer have horizontal displacements. These displacements are called "binocular disparity" and cause the user to sense a three-dimensional image appearing on, in front of or behind the screen.
Since the audience has to use the shutter glasses to see an image on the above stereoscopic image display apparatus, it is easy for him to see the apparatus located ahead but difficult to see something located near him.
Accordingly, when the user switches television channels or adjusts the volume, he has to struggle with his shutter glasses on or take off the glasses, in order to find an infrared remote controller as the conventional control means.
A parallax barrier binocular type stereoscopic image display apparatus is exemplified as another type of stereoscopic display apparatus. In this apparatus, images for the left eye and ones for the right eye are arranged alternately inside the slit aperture of the apparatus, so that the left eye can see only the image for the left eye, and the right eye only the image for the right eye. As a result, the observer or user can see a stereoscopic image.
However, the movable range of the eyes in which a stereoscopic image can be seen (i.e. the movable range of the user's position) is principally narrow. In light of this, the display apparatus includes a lamp for informing the user of a position in which the user can correctly observe a stereoscopic image. Further, the apparatus also includes a sensor for sensing the present position of the user. In accordance with the sensed position of the user, the display function of the apparatus is corrected so as to enable him to see a clear stereoscopic image.
This display apparatus is also disadvantageous in that it is necessary for the user to take his eyes off the screen or struggle to find a remote controller, in order to switch channels or change the volume. In addition, since the control based on the measured position of the user starts to work normally after the user finds the remote controller and returns to the predetermined position, lots of time is required before he can observe stereoscopic images again.
As described above, the conventional three-dimensional image display apparatuses are disadvantageous in that the user has to struggle to find its remote controller in order to, for example, switch channels while watching the display apparatus.